The invention pertains to a double trimming shears, with a stationary lower knife and a lowerable and raisable driven upper knife, wherein the upper knife is mounted on an upper-knife carriage, which is guided by a carriage guide, wherein, for the guidance of the carriage guide, a first eccentric shaft and a second eccentric shaft are provided on the carriage guide.
Double trimming shears are usually used to trim sheets of metal to their final width. Double trimming shears are usually driven by crank drives, but the cutting movement of these drives cannot be adjusted. The carriage guide of the upper-knife carriage is attached to an eccentric shaft in the upper area and to a second eccentric shaft in the lower area. In the lower area, the eccentric shaft is usually supported by a connecting rod. The height of the guide of the upper-knife carriage can be adjusted by means of the eccentric shaft provided in the upper area. The coupling of the eccentric shaft in the lower area by means of a connecting rod results in a horizontal displacement of the carriage guide. In cases where the carriage guide of the upper-knife carriage is adjusted in the lower area by means of a connecting rod in a manner separate from the upper area, the upper-knife carriage can experience undesirable tilting.